Added deny(const_eval_mutable_ptr_in_final_value) attribute to all tests that were expecting the hard error for it.

I attempted to do this in a manner that preserved the line numbers to reduce the
review effort on the resulting diff, but we still have to deal with the
ramifications of how a future-incompat lint behaves compared to a hard-error (in
terms of its impact on the diagnostic output).

Author: pnkfelix

tests/ui/consts/const-eval/heap/alloc_intrinsic_untyped.rs

@@ -2,7 +2,7 @@
 #![feature(const_heap)]
 #![feature(const_mut_refs)]
 use std::intrinsics;
-
+#[deny(const_eval_mutable_ptr_in_final_value)]
 const BAR: *mut i32 = unsafe { intrinsics::const_allocate(4, 4) as *mut i32 };
 //~^ error: mutable pointer in final value of constant
 

tests/ui/consts/miri_unleashed/mutable_references.rs

@@ -1,5 +1,5 @@
 //@ compile-flags: -Zunleash-the-miri-inside-of-you
-
+#![deny(const_eval_mutable_ptr_in_final_value)]
 use std::cell::UnsafeCell;
 
 // a test demonstrating what things we could allow with a smarter const qualification

tests/ui/consts/miri_unleashed/mutable_references.stderr

@@ -3,30 +3,83 @@ error: encountered mutable pointer in final value of static
    |
 LL | static FOO: &&mut u32 = &&mut 42;
    | ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/mutable_references.rs:2:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/mutable_references.rs:7:1
+   |
+LL | static FOO: &&mut u32 = &&mut 42;
+   | ^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>: encountered mutable reference or box pointing to read-only memory
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 8, align: 8) {
+               ╾ALLOC0<imm>╼                         │ ╾──────╼
+           }
 
 error: encountered mutable pointer in final value of static
   --> $DIR/mutable_references.rs:10:1
    |
 LL | static BAR: &mut () = &mut ();
    | ^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
 
 error: encountered mutable pointer in final value of static
   --> $DIR/mutable_references.rs:15:1
    |
 LL | static BOO: &mut Foo<()> = &mut Foo(());
    | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
 
 error: encountered mutable pointer in final value of static
   --> $DIR/mutable_references.rs:22:1
    |
 LL | static MEH: Meh = Meh { x: &UnsafeCell::new(42) };
    | ^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/mutable_references.rs:22:1
+   |
+LL | static MEH: Meh = Meh { x: &UnsafeCell::new(42) };
+   | ^^^^^^^^^^^^^^^ constructing invalid value at .x.<deref>: encountered `UnsafeCell` in read-only memory
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 8, align: 8) {
+               ╾ALLOC1╼                         │ ╾──────╼
+           }
 
 error: encountered mutable pointer in final value of static
   --> $DIR/mutable_references.rs:25:1
    |
 LL | static OH_YES: &mut i32 = &mut 42;
    | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/mutable_references.rs:25:1
+   |
+LL | static OH_YES: &mut i32 = &mut 42;
+   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered mutable reference or box pointing to read-only memory
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 8, align: 8) {
+               ╾ALLOC2╼                         │ ╾──────╼
+           }
 
 error[E0594]: cannot assign to `*OH_YES`, as `OH_YES` is an immutable static item
   --> $DIR/mutable_references.rs:32:5
@@ -62,6 +115,82 @@ help: skipping check that does not even have a feature gate
 LL | static OH_YES: &mut i32 = &mut 42;
    |                           ^^^^^^^
 
-error: aborting due to 6 previous errors; 1 warning emitted
+error: aborting due to 9 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0080, E0594.
+For more information about an error, try `rustc --explain E0080`.
+Future incompatibility report: Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/mutable_references.rs:7:1
+   |
+LL | static FOO: &&mut u32 = &&mut 42;
+   | ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/mutable_references.rs:2:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/mutable_references.rs:10:1
+   |
+LL | static BAR: &mut () = &mut ();
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/mutable_references.rs:2:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/mutable_references.rs:15:1
+   |
+LL | static BOO: &mut Foo<()> = &mut Foo(());
+   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/mutable_references.rs:2:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/mutable_references.rs:22:1
+   |
+LL | static MEH: Meh = Meh { x: &UnsafeCell::new(42) };
+   | ^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/mutable_references.rs:2:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/mutable_references.rs:25:1
+   |
+LL | static OH_YES: &mut i32 = &mut 42;
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/mutable_references.rs:2:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-For more information about this error, try `rustc --explain E0594`.

tests/ui/consts/miri_unleashed/mutable_references_err.rs

@@ -2,7 +2,7 @@
 //@ normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
 //@ normalize-stderr-test "([0-9a-f][0-9a-f] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> "HEX_DUMP"
 #![allow(invalid_reference_casting, static_mut_refs)]
-
+#![deny(const_eval_mutable_ptr_in_final_value)]
 use std::cell::UnsafeCell;
 use std::sync::atomic::*;